- Mix together all ingredients in a small bowl. Taste and adjust seasoning, as needed. Refrigerate until ready to serve.
- Preheat oven to 180°C (350°F). Line a baking sheet with parchment paper and lightly oil it. Place onion slices on baking sheet and season with salt to taste.
- Bake in centre of oven for 40 minutes, or until onion is golden brown. Set aside.
- In a large bowl, combine first 6 ingredients.
- Avoid pressing down on the mixture so the meat doesn’t harden.
- Cook about 15 mL (1 tbsp.) of the mixture to verify seasoning. Adjust if necessary.
- Lightly oil hands and form 4 patties 10 cm (4 in.) in diameter.
- Preheat the barbecue to medium-high and lightly oil the grill.
- Grill patties about 3 minutes per side, turning only once while they cook. The meat should be fully cooked.
- Grill English muffins about 1 minute per side. Spread them with lime mayonnaise and garnish with tomato slices and fried onion.
- Avoid turning meat too soon after it starts cooking so it won't stick to the barbecue grill.
- Turn patties only once without pressing down on them while cooking, so they don't become hard.
Use leftover fried onion in a pasta or legume salad, a sandwich, or a pasta dish.
You can also prepare these burgers using ground pork. In this case, omit the water and season more generously with salt. Grill for 8 minutes on the barbecue, about 4 minutes per side, until meat is well done.